This invention relates generally to flexible belts and more particularly to a belt that exhibits an anti-backbending characteristic that is useful in conveyor type applications.
Belts having an anti-backbend characteristic are useful in various applications wherein the belt must support a certain load carried by it, as for example conveyor belts. This invention is applied to those type applications wherein either the belt alone must support the load carried by it or it is applied as a secondary support means wherein a first conveyor is a primary driven belt and carries the load but wherein a secondary belt is used to support the primary belt when the load is applied in the area between the drive and take-up pulleys. An application of this latter type is described in a co-pending application entitled, "Tracked Vehicle Suspension" and filed concurrently herewith and issued to U.S. Pat. No. 4,221,272 on Sept. 9, 1980. In that application a suspension system is described wherein the primary belt is a snowmobile snowtrack and it is supported on the ground side by a secondary belt that is positioned inside of the track, along its path of travel, and engaged and driven by the track but which presents a resistance to back bending and thus holds the track to the ground as it follows the terrain.
The belt of this invention is designed to operate either singly or in combination with a primary conveyor and is contrasted to other types of belts in the art by virtue of the fact that the compression section of the belt faces outwardly of the pulley axes of its path of travel rather than inwardly as is conventional. In this circumstance the tension member is closest to the inward facing surface that engages the pulley, while the compression section comprises substantially incompressible material and is closest to the outward facing surface of the belt.
A principal object of the invention therefore is to provide a belt that is flexible when passing around pulleys but which presents a resistance to backbending when straightened out between the pulleys. The foregoing and other objects and advantages are accomplished in an anti-backbending belt comprising: an endless flexible belt for operation between at least two pulleys and having a molded elastomeric body and opposite inside and outside face surfaces of which the inside surface is directed toward the pulley axes when the belt is in use, said belt comprising a plurality of longitudinal high tensile modulus cords embedded in the belt nearer the inside surface and a layer of substantially incompressible material facing outwardly and forming the outside surface, said incompressible material comprising at least 50% of the total surface-to-surface thickness of said belt to provide an anti-backbend characteristic to the belt when it is in its straightened position between the pulleys.